Electronic and structural reconstruction in titanate heterostructures from first principles

Recent advances in transition metal oxide heterostructures have opened new routes to create materials with novel functionalities and properties. One direction has been to combine a Mott insulating perovskite with an electronic d$^1$ configuration, such as LaTiO$_3$, with a band insulating d$^0$ perovskite, such as SrTiO$_3$. An exciting recent development is the demonstration of interfacial conductivity in GdTiO$_3$/SrTiO$_3$ heterostructures that display a complex structural motif of octahedral rotations and ferromagnetic properties similar to bulk GdTiO$_3$. In this talk we present our first principles investigation of the interplay of structural, electronic, magnetic, and orbital degrees of freedom for a wide range of d$^1$/d$^0$ titanate heterostructures. We find evidence for both rotation driven ferroelectricity and a symmetry breaking electronic reconstruction with a concomitant structural distortion at the interface. We argue that these materials represent an ideal platform to realize novel functionalities such as the electric field control of electronic and magnetic properties.